Three types of auxiliary lens holding cylinders are known which are used for wide-angle, long-range and close-range photography, respectively, and these cylinders are mounted on the camera body with a lens of an appropriate focal length therein One type has in addition to the appropriate focal length lens a built-in plus lens fixed therein, one has a built-in minus lens fixed therein, and one has no built-in lens. They are generally referred to simply as a "lens" with a designation of the focal length of the combination of the appropriate lens and the built-in lens, if any.
Appropriate ones of these lens holding cylinders are selectively used for wide-angle, long-range or close-range photography. Thus all three types of cylinders must be available if all three types of photography are to carried out, and this is uneconomical and is also undesirable from the standpoint of convenience.
For this reason, a single auxiliary lens holding cylinder which can be used for all three types of photography, i.e., wide-angle, long-range and close-range, that is, one economical and portable auxiliary lens holding cylinder has long been in demand.